Modular mechanism for office chairs and the like

ABSTRACT

Mechanism ( 1 ) for office chairs and the like, comprising a main body ( 2 ), a support element ( 7 ) for a back ( 8 ) turnably engaged with the main body ( 2 ) through first mounting means ( 9 ), a propelement ( 10 ) for a seat ( 11 ) mounted onto the main body ( 2 ) through the second mounting means ( 12 ), in which the mounting means ( 9 ) are partially or wholly arranged within said main body ( 2 ). It can also be provided for at least two Types of mounting means ( 12 ) that can be interchangeably mounted onto the main body ( 2 ), so as to change the type of mechanism ( 1 ) according to type of a second mounting means ( 12 ) being used. It can be provided for connecting means ( 16 ) between the prop element ( 10 ) and the support element ( 7 ).

The present invention relates to a mechanism for office chairs and the like. As is known, office chairs generally have portions with adjustable height and inclination. Said chairs can have the back, and sometimes the seat as well, with adjustable inclination with respect to a main body, for instance box-shaped, which is engaged with an upper end of an upright defining the vertical stand of the chair. The connection between main body and upright is carried out by means of an element substantially shaped as a frustum of cone, integral with the main body and receiving the upper end of the upright. It is known about mechanisms enabling the inclination only of the back, known as “permanent contact” mechanisms, in which the seat is fastened to the main body of the chair whereas the back is hinged to said body. It is further known about mechanisms enabling the independent inclination of back and seat, known as “asynchronous” mechanisms, in which both the back and the seat are hinged outside to the main body.

Then there are mechanisms enabling the simultaneous and proportional inclination, according to a given ratio between the angles, of back and seat, known as “synchronous” mechanisms. In this case the back and the seat are mounted onto the main body through corresponding hinges and are further connected by means of another hinge or connecting element, outside the main body. As is well known, in order to prevent the formation of a three-hinge arc, which would prevent any movement, a slot enabling the reciprocal movement of the parts is provided on one of the three mounting spots. It is also known about mechanisms with inclinable back and seat, integral one with the other, known as “swinging” mechanisms, in which a global back-seat structure is mounted onto a plate hinged to the main body. In all the cases referred to above, it is provided for elastic elements contrasting inclination and the oscillation of the inclinable portions can be selectively prevented by means of suitable known blocking devices, which are generally operatively associated with the back, but can also be associated with the seat and in particular, in the case of asynchronous mechanism, it can be provided for one blocking element for the back and one for the seat.

The prior art, briefly described above, shows some drawbacks.

First of all, all known mechanisms have a high level of design and structural complexity, since in order to obtain the desired movement the mounting position of back and seat should be chosen in a particularly careful way for each type of mechanism. Moreover, known mechanisms should always be designed specifically for each type of desired application, and therefore the possibility to exploit large-scale productions with standard parts is quite limited. This involves high design and installation costs for manufacturing plants, high storage and in general manufacturing costs for chair mechanisms. Furthermore, due to the strong design limitations of said mechanisms, the aesthetical appearance thereof and of the chairs onto which they are mounted is often strongly limited.

Under these circumstances the technical task underlying the present invention is to conceive a mechanism for office chairs and the like that can basically obviate the aforesaid drawbacks. Within said technical task an important aim of the invention is to conceive a mechanism for office chairs granting a high design freedom for the mechanism, for the parts connected thereto and for the chair as a whole. Furthermore, the invention aims at conceiving a mechanism for office chairs that can be carried out in a simple and fast way. Another aim of the invention is a mechanism for office chairs that can easily suit various needs, and that can thus be modified in order to carry out a plurality of types of mechanisms for chairs (for instance swinging, synchronous, asynchronous, permanent contact mechanisms). A further aim of the invention is to provide for a mechanism enabling to keep the aesthetical appearance of the mechanism and of the chair substantially unchanged in the different types of mechanism, for instance from swinging to synchronous mechanism. The invention further aims at conceiving a mechanism that is particularly compact. Eventually, a technical aim of the invention is to conceive a mechanism for office chairs with quite low design and manufacturing costs. The technical task and the aims referred to are basically achieved by a mechanism for office chairs characterized in that it comprises one or more of the technical solutions hereinafter claimed. The following contains to a merely indicative and non-limiting purpose the description of a preferred though not exclusive embodiment of a mechanism according to the invention, shown in the accompanying drawings, in which:

FIG. 1 shows a perspective view of a first embodiment of a mechanism for office chairs according to the present invention;

FIG. 2 is a partially sectioned lateral view of the mechanism of FIG. 1 applied to an office chair;

FIG. 3 is a view from above of the mechanism of FIG. 1;

FIG. 4 is a view like the one in FIG. 2 showing a variant of the first embodiment of the mechanism;

FIG. 5 is a view like the one in FIG. 2 showing a second embodiment of the mechanism;

FIG. 6 is a view like the one in FIG. 2 showing a third embodiment of the mechanism;

FIG. 6 a is a view from above of a detail of the mechanism of FIG. 6;

FIG. 7 is a view like the one in FIG. 2 showing a fourth embodiment of the mechanism;

FIG. 8 is a view like the one in FIG. 2 showing a fifth embodiment of the mechanism;

FIG. 9 is a view like the one in FIG. 2 showing a sixth embodiment of the mechanism;

FIG. 10 is a view like the one in FIG. 2 showing a seventh embodiment of the mechanism;

FIG. 11 is a view from above of a eighth embodiment of the mechanism;

FIG. 12 is a lateral view of the mechanism of FIG. 11;

FIG. 13 is a lateral view of a variant of the mechanism of FIG. 12;

FIG. 14 shows the mechanism of FIG. 13 in an inclined operating position;

FIG. 15 shows a lateral view of a main body being part of the mechanisms of FIGS. 11-14.

With reference to the figures just mentioned, a mechanism for office chairs and the like according to the invention is globally referred to with the numeral 1. The mechanism 1 comprises a main body 2 engaging by means of a connecting element 3 with an upper end of an upright 4 defining the vertical stand of a chair 5. A known base 6 is connected to the lower end of the upright 4.

The mechanism 1 further comprises a support element 7 for a back 8 of the chair 5, turnably engaged with the main body 2 by means of first mounting means 9, and a prop element 10 for a seat 11 of the chair 5 mounted onto the main body 2 by means of second mounting means 12. The mechanism 1 further comprises elastic support means, which are known and therefore not shown in the figures, placed at least between the support element 7 and the main body 2.

According to the present invention the first mounting means 9 are at least partially arranged within the main body 2, i.e. they comprise at least a first portion 9 a extending within the main body 2. Advantageously, also the second mounting means 12 are at least partially arranged within the main body 2, and therefore comprise at least a corresponding first portion 12 a extending within the main body 2, beyond a possible second portion 12 b, extending outside the main body 2. The support element 7 of the back 8 and the prop element 10 of the seat 11 can be applied onto the corresponding mounting means on the first or second portions 9 a, 12 a, 9 b, 12 b.

Advantageously, the first and/or second mounting means 12 can be wholly housed in the main body 2, without second portions 9 b, 12 b extending outside said main body 2. In such a case the support element 7 and the prop element 10 are mounted directly onto the first portions 9 a, 12 a and get out of the upper portion of the main body 2 through convenient openings.

Advantageously, the main body 2 can comprise a support frame 13 that can be engaged with the upper end of the upright 4, and a cover element 14 that can be associated outside with the support frame 13. In such a case the first and second mounting means 9, 12 are arranged at least partially within at least the cover element 14, or preferably wholly within the cover element 14. Advantageously, said mounting means 9, 12 can therefore be arranged also within the support frame 13, either partially or wholly. Preferably the cover element 14 can be equipped with fastening means 15, such as conventional hooking systems, by means of which it can be associated in a removable way with the main body 2 so as to be interchangeable with a plurality of cover elements 14 having for instance different aesthetical features or so as to enable the maintenance of the mechanism. Advantageously the cover element consists of a pair of half-shells that can be associated one with the other and with the support frame 13.

Advantageously, the mechanism 1 comprises at least two types of second mounting means 12, which can be mounted onto the main body 2 in an interchangeable way, so as to change the type of mechanism 1 according to the type of mounting means 12 being used. Advantageously, said different types of mounting means 9, 12 can always be applied to the main body 2 on the same fastening spots, thus allowing not to change the main body and to standardize components.

In such a case, the second mounting means 12 comprise a first type of second mounting means 12 for securing the prop element 10 to the main body 2, and at least a second type of second mounting means 12 for turnably mounting the prop element 10 onto the main body 2, thus allowing to carry out two different types of mechanisms (for instance a permanent contact in which the seat 11 is fixed, a synchronous mechanism in which back 8 and seat 11 are inclinable independently) in a simple way, keeping both the main body 2 and the prop element 10 unchanged. An embodiment shown in FIG. 7 shows a permanent contact mechanism 1 in which the support element 7 of the back 8 is turnably mounted by means of the first mounting means 9, whereas the prop element 10 of the seat 11 is secured to the main body 2 by means of the second mounting means 12. By simply replacing the second mounting means 12, which are fixed, with rotating second mounting means 12 it is possible to obtain the asynchronous mechanism 1 shown in FIG. 8, without any further change to be made to the main body 2 or to the prop element 10. Moreover, the mechanism 1 can comprise also at least two types of first mounting means 9, which can be mounted onto the main body 2 in an interchangeable way, so as to change the type of mechanism 1 according to the type of first mounting means 9 being used, for instance going from pins mounted turnably to pins secured onto the main body 2.

The mechanism 1 can further comprise connecting means 16 between the prop element 10 and the support element 7, so as to enable to carry out further types of mechanisms 1. FIGS. 11 and 12 show a traditional “closed” asynchronous mechanism 1, carried out by mounting onto the main body of FIG. 15 a prop element 10 and a support element 7 through conventional first and second mounting means 9, 12. FIGS. 13 and 14 shows an execution variant of said mechanism 1, in which by replacing the first and second mounting means 9, 12 with another type of mounting means 9, 12, an “open” synchronous mechanism is obtained, which uses the same main body 2 and the same mounting spots as the support and prop element. In such a case it is provided for connecting means 16, which are placed outside the support frame 13 and can be within a possible cover element 14, consisting of a direct rotating connection between the prop element 10 and the support element 7. At least one of the hinges is provided with a slot allowing to prevent the formation of a three-hinge arch which would prevent the movement of the elements. Obviously, it can be provided for other types of mounting means, all of which enable to obtain all known types of mechanisms keeping the main body 2, and preferably also the prop element 10 and the support element 7, unchanged.

Advantageously, the connecting means 16 are housed within the main body 2, at least within the cover element 14 and preferably within the support frame 13. The connecting means 16 can be indirectly (FIGS. 1-6) or directly (FIG. 9) associated with the prop element 10 and with the support element 7. In particular, said connecting means 6 can be associated to the first mounting means 9 and to the second mounting means 12, as in the embodiments shown in FIGS. 1-6.

In a first embodiment, shown in FIGS. 1 to 4, the connecting means 16 comprise at least a first crank 17 and a connecting rod 18 turnably associated one with the other and operatively connected between the prop element 10 and the support element 7 so as to transmit motion. Advantageously, the connecting means 16 comprise a second crank 19 turnably associated with the connecting rod 18 and with the prop element 10. Preferably, the cranks 17, 19 consist of rotating elements integral with the support and prop elements, respectively, Said cranks 17, 19 can be secured directly to the support and prop elements or can be advantageously applied onto the mounting means (as shown in FIG. 1).

Preferably, as shown in FIGS. 1 to 3, the mechanism 1 can comprise a pair of connecting means 16 arranged symmetrically on two opposite sides of the main body 2, so as to give the mechanism 1 a higher stability and a greater resistance. Advantageously, said connecting means 16 can be provided with at least two different mounting positions defining a different ratio between the movement of the prop element 10 and the movement of the support element 7. For instance, FIG. 4 shows an execution variant of the mechanism 1 of FIG. 2 in which the connecting rod 18 is applied to the two cranks 17, 19 in a different mounting position, with a different angle, defining a different ratio between the rotation of the support element 7 and the rotation of the prop element 10, for instance by means of a plurality of mounting holes 28.

It is thus possible, by changing the mounting position of the connecting means 16, to shift from a synchronous mechanism 1 (FIG. 2) to a swinging mechanism 1 (FIG. 4).

In a second embodiment, shown in FIG. 5, the connecting means 16 comprise at least a first pulley 20 associated and rotating integrally with the support element 7, a second pulley 21 associated and rotating integrally with the prop element 10 and a flexible connecting element 22 between the first and the second pulley 20, 21. The first pulley 20 and the second pulley 21 are advantageously applied onto the mounting means, but could also be directly secured onto the support and prop elements. The flexible connecting element 22 could consist for instance of a belt or also a chain, in which case the first 20 and the second pulley 21 are toothed wheels.

In a third embodiment, shown in FIG. 6, the connecting means 16 comprise at least a gear consisting of at least a first toothed wheel 23 associated and rotating integrally with the support element 7, and a second toothed wheel 24 associated and rotating integrally with the prop element 10. The second toothed wheel 24 is operatively connected to the first toothed wheel 23 so as to transmit motion between the prop element 10 and the support element 7. The first and second toothed wheel 24 are applied onto the mounting means, and in particular onto the first portions. Advantageously, the connecting means 16 can further comprise at least a third toothed wheel 25, placed between the first toothed wheel 23 and the second toothed wheel 24. As an alternative, friction wheels can be used instead of toothed wheels.

The connecting means 16 can be further equipped with means 26 for changing the ratio between the prop element 10 and the support element 7. For instance, said change means 26 can comprise, in said embodiment, a change gear arranged instead of the third toothed wheel 25, operatively placed between the prop element 10 and the support element 7, which can be actuated manually by the operator by means of a corresponding control lever (not shown). Said change gear is schematically shown in FIG. 6 a, in which the first mounting means onto which the first toothed wheel 23 is secured, the second mounting means onto which three separate toothed wheels 24 are secured, and an intermediate axis 29 onto which a third toothed wheel 25 is secured and a joint element 30 is slidingly mounted, can be seen. Said joint element 30 comprises three toothed wheels that can be alternatively associated with the three second toothed wheels 24 according to the position of the joint element 30 on the intermediate axis 29. The user can therefore change, by simply moving the joint element 30 with a suitable actuator (not shown), the type of mechanism from swinging (if the transmission ratio is 1:1) to various synchronisms (if the ratio is other than 1:1) up to a permanent contact mechanism, which can be obtained by putting the change gear in neutral and blocking the seat.

FIG. 9 shows a sixth embodiment in which the connecting means 16 are directly associated with the prop element 10 and with the support element 7. In said embodiment the connecting means 16 comprise at least an oblong connecting element 27 turnably associated with the prop element 10 and with the support element 7. In order to enable the change of the ratio between the movement of the support element 7 and the movement of the prop element 10, it can be provided for a plurality of mounting positions of said connecting means 16. The oblong connecting element 27 can then be mounted, for instance by means of a plurality of mounting holes 28 made on the prop element 10 and/or on the support element 7, into a plurality of operating positions corresponding to different connecting ratios between said elements.

FIG. 10 shows a seventh embodiment in which the connecting means 16 comprise a simple rotating coupling 31 between the prop element 10 and the support element 7. The rotating coupling 31 is equipped with a hinge allowing to prevent the formation of a three-hinge arch. In said embodiment the prop element 10 and the support element 7 are conveniently shaped so as to overlap in a given spot. The connecting means 16 can be arranged outside the main body 2, but are preferably arranged within the main body 2 and therefore within the support frame 13 or at least within the cover element 14. In all the embodiments shown it is further provided for known elastic prop means (not shown in the figures), such as a spring, placed between each independently rotating portion and the main body 2, and then at least between the support element 7 and the main body 2. Therefore, by means of a mechanism 1 according to the present invention it is possible to obtain easily all types of known mechanisms, i.e. “permanent contact” mechanisms, in which the prop element 10 of the seat 11 is integral with the main body 2 and the only inclinable portion is the back 8, “synchronous” mechanisms, in which the prop element 10 of the seat 11 is turnably associated with the main body 2 and with the support element 7 of the back 8 so as to swing proportionally to the oscillation of the support element 7 of the back 8, and “swinging” mechanisms, in which the prop element 10 of the seat 11 is secured to the support element 7 of the back 8 so as to swing integrally with the latter. “Asynchronous” mechanisms can also be carried out, in which the prop element 10 of the seat 11 is turnably associated with the main body 2 so as to swing independently with respect to the main body 2, and “free floating” mechanisms, in which the seat 11 can be inclined and secured in different operating positions. Obviously, various changes and variants can be made to the device according to the present invention without leaving the framework of the inventive idea characterizing it. All details can be replaced by other technically equivalent elements, and in practice all materials used, as well as sizes, can be as desired according to the various needs.

The mechanism according to the present invention, described above from a basically structural point of view, works as follows. The invention allows to carry out one type of main body 2, support element 7 and prop element 10, which can be connected through mounting means 9, 12 and possibly connecting means 16, which enable to obtain different mechanisms 1 starting from the same main components. Therefore, according to the kind of desired mechanism, it is possible to assemble only the mounting means 9, 12 and the possible connecting means 16 referred to above conveniently, without changing in any way the main elements of the chair. The actuation of the various portions of the mechanism 1 during use takes place by means of conventional control levers, which enable to actuate conventional blocking devices. If the mechanism 1 is equipped with a change gear 26, the type of mechanism 1 can also be changed during use.

The invention achieves important advantages. As a matter of fact, a mechanism according to the present invention gives a great freedom of design for the mechanism, for the parts connected thereto and for the chair. Moreover, a mechanism according to the invention has a simple and compact structure and can be carried out quite fast. The invention further enables to carry out a “swinging” mechanism in which seat and back are separate elements instead of being integral one with the other. It should further be pointed out that the mechanism can be easily adapted and modified to any kind of need, and can therefore enable to carry out all known types of mechanisms for chairs with quite a small number of changes. The invention allows indeed to standardize many of the parts of the mechanism, and enables therefore to manufacture a wide range of different mechanisms, which can have unchanged size, main structure and aesthetical appearance of many elements and of the chair, such as for instance the main body, with great advantages from an economic point of view and considering the simplification of all manufacturing processes. Furthermore, the invention allows to obtain an extremely flexible mechanism, which can also enable the adjustment of the mechanism by the operator. It should therefore be pointed out that the mechanism according to the invention enables to considerably reduce all design and manufacturing costs. 

1-33. (canceled)
 34. Mechanism for office chairs and the like, comprising: a main body (2) that can be engaged with an upper end of an upright (4) defining the vertical stand of a chair (5), a support element (7) for a back (8) of the chair (5) turnably engaged with said main body (2) by means of first mounting means (9), a prop element (10) for a seat (11) of the chair (5) mounted onto said main body (2) by means of second mounting means (12), and elastic prop means placed at least between said support element (7) and said main body (2), characterized in that said first mounting means (9) are at least partially arranged within said main body (2).
 35. Mechanism according to claim 34, characterized in that also said second mounting means (12) are at least partially arranged within said main body (2).
 36. Mechanism according to claim 34, characterized in that said first and/or said second mounting means (12) are wholly housed in said main body (2).
 37. Mechanism according to claim 34, characterized in that it further comprises connecting means (16) between said prop element (10) and said support element (7).
 38. Mechanism according to claim 37, characterized in that said connecting means (16) are arranged at least partially within said main body (2).
 39. Mechanism according to claim 38, characterized in that said connecting means are arranged wholly within said main body (2).
 40. Mechanism according to claim 37, characterized in that said connecting means (16) are associated directly with said prop element (10) and with said support element (7).
 41. Mechanism according to claim 37, characterized in that said connecting means (16) are associated indirectly with said prop element (10) and with said support element (7).
 42. Mechanism according to claim 41, characterized in that said connecting means (16) are associated with said first mounting means (9) and with said second mounting means (12).
 43. Mechanism according to claim 37, characterized in that said connecting means (16) are provided with at least two separate mounting positions in which they define a different ratio between the movement of said prop element (10) and said support element (7).
 44. Mechanism according to claim 37, characterized in that said connecting means (16) are equipped with means (26) for changing the ratio between the movement of said prop element (19) and said support element (7).
 45. Mechanism according to claim 44, characterized in that said means (26) for changing the ratio comprise a change gear operatively placed between said prop element (10) and said support element (7).
 46. Mechanism according to claim 37, characterized in that said connecting means (16) comprise at least a first pulley (20) associated and rotating integrally with said support element (7), a second pulley (21) associated and rotating integrally with said prop element (10), and a flexible connecting element (22) between said first (20) and said second pulley (21).
 47. Mechanism according to claim 46, characterized in that said flexible connecting element (22) is a belt.
 48. Mechanism according to claim 46, characterized in that said flexible connecting element (22) is a chain and in that said first (20) and second pulley (21) are toothed wheels.
 49. Mechanism according to claim 37, characterized in that said connecting means (16) comprise at least a first toothed wheel (23) associated and rotating integrally with said support element (7), and a second toothed wheel (24) associated and rotating integrally with said prop element (10) and operatively connected with said toothed wheel (23) so as to transmit motion between the prop element (10) and the support element (7).
 50. Mechanism according to claim 49, characterized in that it further comprises at least a third toothed wheel (25) placed between said first toothed wheel (23) and said second toothed wheel (24).
 51. Mechanism according to claim 49, characterized in that said wheels (23, 24) are friction wheels instead of toothed wheels.
 52. Mechanism according to claim 37, characterized in that said connecting means (16) comprise at least an oblong connecting element (27) turnably associated with said prop element (10) and said support element (7).
 53. Mechanism according to claim 52, characterized in that said oblong connecting element (27) can be mounted onto at lest one of said prop element (10) and support element (7) in a plurality of operating positions corresponding to various connecting ratios between said elements.
 54. Mechanism according to claim 37, characterized in that said connecting means (16) comprise at least a first crank (17) and a connecting rod (18) turnably associated one with the other and operatively connected between said prop element (10) and said support element (7) so as to transmit motion.
 55. Mechanism according to claim 54, characterized in that said connecting means (16) comprise a second crank (19) turnably associated with the connecting rod (18) and with said prop element (10).
 56. Mechanism according to claim 37, characterized in that it comprises a pair of said connecting means (16) arranged symmetrically on two opposite sides of the main body (2).
 57. Mechanism according to claim 37, characterized in that connecting means (16) define a 1:1 transmission ratio between the prop element (10) and the support element (7), so as to obtain the same inclination of back and seat, and therefore a “swinging” mechanism, without a direct fastening between back and seat.
 58. Mechanism according to claim 34, characterized in that said main body (2) comprises a support frame (13) that can be engaged with said upper end of an upright (4) and at least a cover element (14) that can be associated with said support frame (13), said first and/or said second mounting means (12) being placed at least partially within said cover element (14).
 59. Mechanism according to claim 58, characterized in that said first and/or said second mounting means (12) are wholly housed in said cover element (14).
 60. Mechanism according to claim 58, characterized in that said cover element (14) is equipped with fastening means through which it can be associated in a removable way with said main body (2) so as to be interchangeable with a plurality of cover elements.
 61. Mechanism according to claim 34, characterized in that it comprises at least two types of said second mounting means (12), which can be mounted onto said prop element (10) and onto said main body (2) in an interchangeable way, so as to change the type of mechanism (1) according to the type of second mounting means (12) being used.
 62. Mechanism according to claim 61, characterized in that the second mounting means (12) comprise a first type of second mounting means (12) for securing the prop element (10) to the main body (2), and at least a second type of mounting means (12) for turnably mounting the prop element (10) onto the main body (2).
 63. Mechanism according to claim 61, characterized in that it comprises at least two types of said first mounting means (9), which can be interchangeably mounted onto said support element (7) and onto said main body (2), so as to vary the type of mechanism (1) according to the type of first mounting means (9) being used.
 64. Mechanism according to claim 61, characterized in that said at least two types of mounting means (9, 12) can be mounted onto said main body (2) on the same fastening spots.
 65. Mechanism according to claim 61, characterized in that said at least two types of mounting means (9, 12) can be mounted onto said support element (7) and/or onto said prop element (10) on the same fastening spots.
 66. Chair (5) characterized in that it comprises a mechanism (1) according to claim
 34. 